Commercial Imax W80 intermittent.

[diamondgas]

Hi folks,

walked in on the above Imax W80 with the display flashing 08, not in mi's. Reset the boiler and it started up first time although I did notice it hanging on '5', detecting fan. Tried this several times without the '08' fault reappearing, however on the 4th attempt the display error '29' "incorrect tacho signal from fan". Displayed and wouldn't cancel! UNTIL I unplugged the wiring connections to the fan to check them out. Plugged them back in and the flippin thing fired up and wouldn't fault again!!!
There are two side by side in the plant room so I thought I'd give them a start up 'race' The one that had faulted still hangs on '5' a lot longer before pre purge and ignition...

I've left he boilers for now and await the fault returning. In the mean time I wondered if anyone reading this has came across this '08' or '29' intermittent fault?

Any thoughts would be greatly appreciated coz I think I'll be back

AND anyone care to explain what a fan tacho reading is? Coz its the first time I've ever came across its description before

Thanks in advance peeps

 

[SimonJohns]

This boiler has a gauze burner.

Take it out remove fan. And wash thru with water. This can cause the boiler to hang on 5

5 = turn fan on wait for aps and tacho signal

Also check sump for debris.

If you get a tacho fault often it needs a new fan.

 

[SimonJohns]

Do you know how to strip this or would you like me to write it up?

 

[SimonJohns]

Also. A tacho is the built in sensor on modulating fans

A modulating fan does not spin at a fast enough speed to satisfy a aps all the time so would cause nuisance lockouts on low fire.
A tacho is just a way the fan senses it's own rotation speed and uses that to speed up or slow to adjust fire rates

 

[diamondgas]

Cheers Simon. A mental note has been logged for future visit The picture I posted was the same boilers terminations !!

 

[SimonJohns]

I was sad enough to know from the spot the fault thread what boiler you was working on before i read this thread lol

My rule of thumb with an IMAX that I haven't looked after before is to get the burner out and wash it. You will notice an immediate difference in the hang time on 5 after you clean the burner

Do you do muh commercial?

Fans are a comman fault on this boiler. PS fault 14 is thermisters. Manual just says internal failure

 

[diamondgas]

Do you know how to strip this or would you like me to write it up?

You're too kind Simon ... Cheers. I have the mi's but any pointers/things to be aware of would be helpful ... Will I need to order any gasket sets B4 removing the burner?

 

[diamondgas]

I was sad enough to know from the spot the fault thread what boiler you was working on before i read this thread lol

My rule of thumb with an IMAX that I haven't looked after before is to get the burner out and wash it. You will notice an immediate difference in the hang time on 5 after you clean the burner

Do you do muh commercial?

Fans are a comman fault on this boiler. PS fault 14 is thermisters. Manual just says internal failure

Commercial is something very new for me Simon. Qualified 2 1/2yrs ago and am still finding my way around. familiar with ther workings but not enough experience to always be comfortable in fault diagnosing. Love the new challenge it offers though!

 

[SimonJohns]

You're too kind Simon ... Cheers. I have the mi's but any pointers/things to be aware of would be helpful ... Will I need to order any gasket sets B4 removing the burner?

The gaskets are pretty good on the burner. Be careful not to drop the gas pipe fibre washer down the back

Don't forget the 10 washers on the screws on the top.

Leave the fan on until removed from boiler. If its the first time you have removed the fan. I would order the fan gasket. ( btw. You get alot of gaskets with a new fan)

^^^^
Take photos for location of red and blue tubes.

If you have access to a hose. Shower the he in water just to give it a good clean and wash the condense trap out

 

[SimonJohns]

If your new to commercial fault finding

Learn the codes

0 no demand
1 pre purge
2 ignition
3 ch mode (burner lit)
4 dhw mode (burner lit)
5 fan start (looking for aps / tacho)

 

[diamondgas]

Cheers Simon ... Any thoughts on the '08' fault?

I thought the tacho reading would have something to do with the fan as it kicked in after hang '5' & before ignition. Also remember another boiler, think it was a broag, wouldn't light coz of incorrect fan speed detection

Good to get confiration from yourself though

 

[SimonJohns]

I think I've seen an 08 before but cannot remember what it was.

If ideal say it's tacho I would replace fan. But only if it happened twice.

 

[diamondgas]

I think I've seen an 08 before but cannot remember what it was.

If ideal say it's tacho I would replace fan. But only if it happened twice.

I'm exactly that same way regards the fault re-occuring, with most intermitents Simon. Especially the price of these parts!! The fact that I couldn't get the tacho fault to re-occur after unplugging and re connecting the fan had me leaving it working but have that feeling that I'll be back.

Least now I know to do more than just replace the fan

 

[SimonJohns]

I'm exactly that same way regards the fault re-occuring, with most intermitents Simon. Especially the price of these parts!! The fact that I couldn't get the tacho fault to re-occur after unplugging and re connecting the fan had me leaving it working but have that feeling that I'll be back.

Least now I know to do more than just replace the fan

You should be looking about £140-180 for a fan

 

[Billy Bob Bob]

http://www.bhl.co.uk/images/tagged/p/55602-technical-Ideal%20Imax%20Installation%20and%20Servicing%20Instructions%20(April%202009).pdf

is this it? looks like a bigger version of the icos

 

[SimonJohns]

It is a magnified icos. Just better

Honeywell pcb for a start

 

[diamondgas]

http://www.bhl.co.uk/images/tagged/p/55602-technical-Ideal Imax Installation and Servicing Instructions (April 2009).pdf

is this it? looks like a bigger version of the icos

Yeh that's the boyo Mark ... It does look like a big ICOS but the electronics are a heck of a lot different and much more reliable from what I gather

 

[Billy Bob Bob]

its built to a better standard by the looks of it